Refrigerator equipped with a motordriven refrigerating apparatus of the compression type



D c. 4, 194 H. SCHIRRMEISTER 2,390,132

REFRIGERATOR EQUIPPED WITH MOTOR-DRIVEN REFRIGERATING APPARATUS OF THE COMPRESSION TYPE Filed May 23, 1940 Patented Dec. 4, 1945 ansmcnns'ron somrrsn wrrn A Moronmuvsn nsrarcnaa'rmc manuals or 7 'ms COMPRESSION rm Hans Schirrmeistel', Berlin-Siemensstadt, Germany; vested in the Alien Property Custodian Application May 23, In Germany IClaims.

This invention relates to a refrigerator equipped with a motor-driven refrigerating apparatus of the compression type.

To avoid the use of stuillng-boxes in such appsratus, the compressor and the driving motor are, as is well known, arranged in a common sealed housing. In such sealed motor-compressor units, the motor can only be provided with a squirrel-cage rotor. Accordingly, these hermetically-sealed units have hitherto been designed for alternating current only. It has already been proposed to supply the driving motor of such units with alternating current through a contacttype inverter connected to a direct-currentsupply circuit. This renders it possible tooperate 1940, Serial No. 336,692 March a sealed motor-compressor unit, designed for' alternating current, also with direct current. The contact-type inverter may be combined with the refrigerating apparatus or cabinet so as to form a structural part thereof. I

The invention aims at providing a particularly simple design of a contact-type inverter system for the above-mentioned purpose. According to the invention the contact-type inverter for feeding the A. C. motor-compressor unit from a D. C. supply network is driven by an electric motor which forms part of the refrigerating apparatus,

preferably with the motor of a fan for supplying cooling air. Since in refrigerating apparatus of the compression type, having a sealed motorcompressor unit, a special fan is, as a rule, em-

. ployed for carrying 011 the heat of condensation and the waste heat of the motor-compressor set, it is only necessary. according to the invention, to couple a contact-type inverter with the motor shaft of the fan, thus providing a very simple drive for the inverter. This drive is preferably so designed that the oscillating contact of the inverter is operated by the m otor shaft through an eccentric drive.

According to another object of the invention, when employing contact-type inverters care should be taken to cool the contacts in an effective manner, since owing to the continual interruptions of the current considerable amounts of heat are liberated which may cause a deterioration of the contacts.

According to the therefore firmly secured to the contacts of the inverter having a sufficiently large cooling surface incontact with the surrounding air. This arrangement is preferably so designed that the cooling disks secured to the stationary contacts are bell-shaped and surround the cooling disks attached to the movable contacts. By thus designing the cooling disks, a powerful circulation 20 in cross section.

invention cooling disks are of air is obtained by the movements of the contacts, owing to the suction and pressure effects brought about by the cooling disks.

Other objects and features of the invention will be apparent from the following description of the embodiments illustrated diagrammaticallv in the accompanying drawing. Fig. 1 shows a circuit diagram and complete arrangement of a refrigerating apparatus of the compression type.

; 10 Fig. 1A is a sectional view through the lower portion of a household refrigerator showing the relative positions of the elements disclosed in- Flg. 1. a Fig. 2 shows in detail the front view of the drive for a contact circuitbreaker forming a D. C. to A. C. inverter for the purpose of the present invention. Fig. 2A is a side elevational view of Fig. 2. Fig. 3 illustrates the contacts of such an inverter provided with cooling disks as set forth in the foregoing, the disks being shown Referring to Fig. 1, the numeral I denotes the totally enclosed motor-compressor unit. 2 is a motor for operating a fan II serving to supply the refrigerating apparatus, in particular the condenser and the motor-compressor unit, with cooling air. I and l are the movable contact members of an inverting interrupter having stationary contacts III, II and I2, II respectively.

The movable contact members I and I each have a slot I in the upper end thereof which slots receive an eccentric pin 8 extending from disk I on the shaft 6 of motor 2. The numeral 5 denotes the customary thermostat disposed in heat contact with the evaporator. This thermostat connects and disconnects the fan motor 2 and opens and at the same time closes the circuit-of the inverting contact circuit breaker serving to supply alternating current to the unit I. I

When in operation, the motor {is supplied with "D. C. and controlled in response to the refrigeratingtemperature acting on the thermostat I. The motor 2 operates fan II, which fan su plies the unit I with cooling air and at the same time actuates the inverter with contacts I and I so as to supply the unit I with A. C. produced by the inverter from the D. C. supply current.

According to the embodiment of Fig. 2, the disk I carries an eccentric pin I, which in turn penetrates slots I in the upper ends of contact.

members I and I. As shaft I revolves the movsblecontactsoscillatebackandforthsoasto tiveiy. Byvsw s-thcsmplitudeoithecontsct carrier (spring 3), the closure periods during which the unit I is inserted in the circuit may be adjusted in a known manner.

The inverter contacts of devices as shown in Figs. 1, 2 and 2A ma be provided with coolingdisks as exemplified by the embodiment oi. Big. 3.

-In' Fig. 3, the intermediate contact member of the inverting switch is denoted by'la and the two outer contact members by [d and Ho, corresponding, for instance, to the contact members 3 and I0, II respectively in Fig. 2. The members corresponding to contacts 4, l2 and ii are not shown, but obviously may be of an identical construction as members 3a, Ilia and Ma.-

Three cooling disks 24, and 26, for instance of copper, are firmly secured to the three contact members 3a, Ha and Illa respectively. The disk 24, mounted on the intermediate member 3a, consists of a flat circular plate surrounded by a cylindrical portion, while the two'outer disk members 25 and 26 are cup-shaped and substantiall enclose the intermediate disk. The

proximate rims of disks 25 and 26 arenotched as at 25a and 26a respectively to permit oscillation of intermediate member 3a. Due to this design and arrangement of the cooling disks, the oscillatory movement of the contact arm 3a produces a powerful circulation of air, which aids in cooling the contacts, by the suction and pressure effects occurring alternately in the spaces. 21 and 28. The outer surface of the arrangement is preferably exposed to cooling airblown never the contact arrangement in the direction indicated by the arrows, for instance, by means of the tank, ll of the refrigerating apparatus.

It is evident that the cooling disks 24, 25 and 26 shown in Fig. 3 may be employed on many types of oscillatory contactjswitches, irrespective of the manner in which the particular switch is operated. I

What is claimed is:

1. A periodically-operating switching device for converting electric current, in particular for energizing a refrigerating A. C. apparatus from a D. C. source, comprising an intermediate contact and two outer contacts, meansfor oscillating said contacts relatively to one anotherso as to engage. said intermediate contact alternately with one and the other outer contact, an inner disk-like cooling member-secured to said-intenmediate contact, and two outer cooling members secured to said outer contacts respectively, said inner member and said outer members forming together two-chambers of. variable volume communicating with the surrounding air so asJto produce an alternate flow or cooling air due to suction and compression-in said chambers.

2. In a device according-to claim 1, said inner cooling member comprising a disk of good heatconductive material secured to said intermediate ing in said system, said second motorbeing con nected with said supply means and actuating said inverting contact device.

4. In an electric refrigerating apparatus, the

combination of a cold-producing refrigerant circulation system including a compres'sor,'an A. C. motor for actuating said compressor, said motor and said compressor forming a sealed unit, an inverting contact device connected with said unit for energizing said motor with A. C., D. C. supply circuit means connected-with said inverting 'de-' vice, temperature-responsive contact means for controlling said unit in response to the tempera actuated thereby also in response to said temperature.

5. In an electric refrigerating apparatus, the

combination of a cold-producing refrigerant circulation system includinga compressor, an A; C. motor for actuating said compressor, said motor and said compressor forming a sealed unit, current supply means for connecting said unit witha D. C. supply circuit, an inverting contact device inserted between said unit and s'aid current supply means, and an electric fan for supplying said system with cooling air -to cool the refrigerant in said system, said fan having an electromotor connected with said supply circuit, and said inverting contact device being connected with said fan motor to be actuated thereby.

6.'In an electric refrigerating apparatus, the combination of a cold-producing refrigerant circulation system including a compressor, an A. C.

motor .Ior actuating said compressor, said motor and said compressor forming a; sealed unit, current supply means "for connecting said motor with a D. C. supply circuit, an inverting contact device inserted between said motor and said current supply means, and means including a second electromotor for cooling therefrigerant circulating in said system, said second motor being connected with said supply means and having a motor shaft provided with eccentric drive means, said inverting contact device having a movable contact member, and a follower connected with contact, and a cylindrical portion integral with 1 said disk' and surrounding said disk, and said outer cooling members beingcup-shaped and arranged 'to substantially ,enclou' said inner member. y v V 3. In an electric refrigerator, the combination of a cold-producing refrigerant circulation system including a compressor, an A. C. motor for actuating said compressor, said motor and said compressor forming a sealed unit, current supsaid movable contact member and engaging said drive means so that said movable contact member is oscillated by said second motor.

7. In an electric refrigerating apparatus, the combination of a cold-producing refrigerant cirgculation system including a compressor, an A. C. motor for actuating said compressor, said motor and said compressorforming a sealed unit, current supply means for connecting said motor with a D. C. supply circuit, an inverting contact ply means for connecting said motor with a D. C.

' supply, circuit, including an inverting contact device inserted between said motor and said our-- rent supply means, and means including a second electromotor'for cooling the refrigerant circulatdevice inserted between said motor and said current supply circuit, said device having contacts provided with cooling disks of heat-conductive material, and an electrician for cooling therefrigerant in said system, said fan having an electric "otor connected with said supply circuit, inverting contact device being connected with said fan motor to be actuated there- /and said cooling disksbeing arranged rela- HANS scnraams'rsa.

tive to said fan so asto be exposed to the cool-- air mpplied bysaid tan. 

